.500 Slap?

[Gifted]

Figured I'd cross post this to maximize coverage. Whad'ya think?

There was a guy in while I was hanging out. He had a 7.62x25 load with him that he was looking at loading. It was a 50 grain .223 in a sabot. We talked a bit, he wanted to find loading supplies so he could mess around with them for less. It got my imagination going, and I figured why not?

.500 S&W+.30 bullet+sabot.

I'm presuming nobody's loaded it before. Probably have to make the sabots, but what kind of performance would you get out of this load?

And unrelated, how do you pronounce sabot? We talked a bit about that, too, but couldn't decide if the original French pronounciation was commonly used, or the American alteration.

 

[Shovelhead]

s - a (as in pat) - b - o (long O sound) - T (is silent)

 

[cheygriz]

say-BO (long"O")

Sabots can be found with a google search. They will be 50 BMG sabots for use in the M-2 machine gun with the .30 M-2 AP bullet. As for cutting them down for the use you propose, it theoretically could be done if you're patient, handy with tools, and determined.

If you do it, let us know your results. GOOD LUCK!!

 

[trickyasafox]

excuse me for being nieve, but whats the purpose of this? what do you gain? im all for just because tinkering, but i dont understand what sabots do, will you gain velocity? accuracy? cool factor?

 

[Fumbler]

excuse me for being nieve, but whats the purpose of this? what do you gain? im all for just because tinkering, but i dont understand what sabots do, will you gain velocity? accuracy? cool factor?

Sabots (French for "shoe") wrap around the sides and rear of the projectile. They're basically like shot wads in shotgun loads, they look like cups with slits in the sides. As the bullet + sabot exits the barrel, air pulls the sides of the sabot backward like petals and the sabot is shed off.
They allow you to shoot a projectile that is smaller than the bore of the barrel.
Using a sabot basically transfers the energy of a large diameter projectile into velocity. Remington factory loads 30-06 Accelerator loads which are a .224" bullet in a sabot. It will launch the lil .22 well above the 4000fps mark.

The military developed the .30 SLAP (Saboted Light Armour Piercing) rounds as an extended range light armour piercing cartridge. It is a .50BMG loaded with .30 cal bullets in a .50 cal sabot. As I understand it, the cartridge was a failure because the twist rate of .50 BMGs are not well suited for the .30 cal bullets, so you get the extended range, but the bullet isn't properly stabilized and accuracy suffered.

 

[50 Shooter]

The .50 BMG sabot/SLAP round is different then your standard .30 cal projo and needed a special barrel/chamber. That's why they had some of the M82's made with a SLAP chamber. The SLAP round is actually about a 355 gr tungsten projo. http://www.globalsecurity.org/military/systems/munitions/slap.htm

There is some .50/.30 sabot wannabe stuff out there but it doesn't even come close to the real thing.

 

[Gifted]

As I understood it it worked well in the M2, but the Barretts had trouble with the muzzle brake. Which means you can't use them in the M82.

 

[50 Shooter]

The M82's that fired the sabot's had a SLAP chamber and the muzzle brakes were opened up to allow for the sabot. I was told that Olin/Win. re-engineered the sabots to stay together longer to give it enough time to exit the brake.

If you can find a Desert Storm M82 with a SLAP chamber it will have to be rebarreled if you plan to shoot it. That's if you want to ruin it's collectors value.

 

[Gifted]

So do you have to have a special chamber to shoot SLAP in an M2? Seems to me that it was designed to work in the MG, and so would be designed to work in the same chamber as the ball ammo. I'm missing something here.

 

[50 Shooter]

Seeing how you can adjust the headspace on the M2 it shouldn't be a problem, that and the fact that the chambers are a bit looser.

Shooting ball ammo out of a SLAP chambered M82 will give you horrible results as far as accuracy goes. I believe the chambers were made looser and a bit longer to accept the SLAP round.

 

[Fumbler]

Why do they have to be sloppier for the SLAP cartridges?
The only reason I can think of is for feeding reliability.
If the SLAP barrels don't shoot the .50BMG well could it be that the twist rates are different?

 

[50 Shooter]

Not sure if they used a different twist rate for the SLAP M82's, that would be a question for Barrett. I think they had a longer chamber to allow for the the SLAP round. I would have to measure one that I have to see if it's ogive(?) area is bigger/longer then a standard round.

The M2's chamber is looser to allow for ammo variances and any crud that might get into the action while in the field.